Last updated
February 14, 2024

Understanding MX Records and Their Role in Email Delivery

Brian Wu

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Launching an email campaign involves comprehensive preparation beyond crafting messages and selecting recipients. 

To ensure a seamless flow of communication—where emails not only reach their intended targets but also allow you to receive responses efficiently—a crucial step lies in examining your Mail Exchange (MX) records. This might seem like a minor detail, but the mechanics of receiving emails extend far beyond a server's ability to parse domain names. 

Understanding and configuring your MX records correctly is foundational to the success of your email outreach, ensuring that your campaign's dialogue is as effective and uninterrupted as possible.

What Are MX Records?

MX records, short for Mail Exchange records, are a type of DNS (Domain Name System) record. They are essential for email routing and email delivery because they route your emails to the appropriate server by including protocols such as SMTP.

They are in charge of directing your messages to the appropriate person. Every MX record directs domain owners to a mail server that is ready to receive emails on their behalf. They serve as a route map for all emails sent, ensuring that your messages arrive at their intended inbox.


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How Do MX Records Work?

Email routing is an essential part of ensuring communication is steadfast. Here's a breakdown of how MX Records orchestrate this journey:

Simple Mail Transfer Protocol, or SMTP

The journey begins with the standard email protocol, known as SMTP (Simple Mail Transfer Protocol). When you click "send" in your email client, SMTP begins to work, figuring out where to send your message.

Email Client to DNS Query

Your email client doesn't inherently know where to send the email based on the recipient's address. It needs directions. This is where DNS queries come into play. The email client asks the DNS server for the MX records associated with the recipient's domain.

DNS Response with MX Records

The DNS responds with a list of MX records for the domain. These records are not just pointers; they're prioritized. Every MX record has a preference value; higher priority is indicated by lower numbers. This system makes sure that emails can be forwarded to the next available mail exchange server in case the primary server is unavailable.

Delivery to the Mail Exchange Server

The SMTP server then makes an attempt to send the email to the mail exchange server with the highest priority after being armed with the MX records. It descends the list according to priority if this server is down until the email is approved for delivery. You can check out MxToolbox’s email server test for better services. 

Final Delivery

The assigned mail exchange server is responsible for forwarding the email to the recipient's inbox once it reaches it. With the help of MX records' background labor, this last stage completes the email's journey and guarantees that the message sent from your email client reaches its intended recipient.

Setting Up & Prioritizing MX Records

Setting up MX Records and giving them priority are essential steps to ensure consistent and efficient e-mail delivery for your domain. These records let you apply load balancing strategies in addition to directing incoming emails to the appropriate server. Here's how to effectively manage this setup:

Step 1: Creating MX Records

You must have access to your domain's DNS settings, usually provided by your hosting company or domain registrar, in order to create MX Records. To lookup different MX records, you can check through a DNS lookup tool.

When adding an MX Record, you specify two main components:

Priority: A numerical value indicating the record's priority relative to other MX Records for the domain. Lower numbers have higher priority.

Server: The hostname of the mail server that will receive the emails. This server must be configured to accept emails for your domain.

Step 2: Prioritizing MX Records

The priority you assign to each MX Record determines the order in which mail servers are attempted for email delivery. For optimal setup:

Primary Server: Assign the lowest priority number (e.g., 0 or 1) to your main mail exchange server. This server will handle the majority of your incoming emails.

Backup Servers: Give backup servers higher priority numbers (10, 20, etc.). In order to provide redundancy and reduce downtime, these servers are used in the event that the primary server is unavailable.

Step 3: Put Load Balancing Into Practice

Load Balancing: If you have multiple mail servers capable of handling your email volume, you can assign them the same priority. This distributes the incoming email load evenly across servers, optimizing performance.

Redundancy: By setting up backup MX Records with higher priority numbers, you create a failover system. Email connectivity is maintained by automatically rerouting email traffic to the backup servers in the event that the primary server fails.

Step 4: Upkeep and Observation

Keep an eye on the performance of your mail servers and change the MX Record settings as necessary. Ensure your backup servers are always ready to take over in case the primary server goes down, and keep your server configurations up to date to handle the emails efficiently.

Troubleshooting: Common MX Records Issues

Resolving typical MX Record problems is essential to combat email deliverability problems. Here's how to recognize and fix a few of the most typical problems:

Emails Are Not Arriving

Check MX Record Configuration: Ensure your MX Records are correctly configured in your DNS settings. 

Verify DNS Propagation: It may take up to 48 hours for your MX Record modifications to take effect on the internet. Check whether your MX Records have propagated correctly using online tools.

Emails Landing in Spam

Inspect Email Authentication Records: Alongside MX Records, ensure that your SPF, DKIM, and DMARC records are correctly set up. These records help verify your domain’s identity and can affect email deliverability.

Check for Blocklisting: Your domain or IP address might be on a blocklist due to previous spam activities. Use blocklist lookup tools to check your status and request removal if necessary.

Server Not Accepting Emails

SMTP Tests: Conduct SMTP connection tests to verify that your mail server is actively accepting connections. These tests can help identify issues with your server configuration or network problems preventing email acceptance.

Examine Server Logs: Server logs can provide clues to why emails are being rejected. Look for error messages related to SMTP communication or specific rejection codes that can guide your troubleshooting.

Blocklists: Organizations and anti-spam entities to prevent unwanted emails from reaching users' inboxes. 

MX Records & Email Verification

Email validation is the process of checking whether an email address is valid, deliverable, and active. This involves several steps to verify a email address, such as:

Server Existence Check: The first step in verifying an email address involves querying the domain's MX records. This step confirms whether the domain is configured to accept emails, indicating that the email address has a valid domain with a mail server ready to receive messages.

Prioritizing Mail Servers: MX records include priority information, which helps email verification services determine which mail server to query first. This is crucial for accurately assessing whether the email service configuration can potentially be delivered.

Directing Verification Requests: By identifying the mail exchange servers through MX records, verification services can directly interact with the server to further validate the email address, using techniques like SMTP protocol without actually sending an email.

To check whether you have a valid and verified email address, you can hop on to Abstract API’s free email validation and verification API.

Examples of MX Record Configurations

MX Record ConfigurationsDomainRecord typePriorityValueTTL (secs)Single Mail Serverexample.comMX10mail.example.com3600Primary and Backup Mail Servermybusiness.comMX10primary-mail.mybusiness.com7200Multiple Backup Serversourorganization.orgMX10smtp1.ourorganization.org86400Load Balanced Configurationexample.netMX10mx1.example.net3600

The Importance of Email Verification in MX Record Configuration

It is impossible to overestimate the significance of email verification in MX record configuration, particularly in the current digital environment where secure email delivery is crucial. Ensuring the validity and deliverability of email addresses is vital when wanting to prevent email spoofing and improving email communication integrity. This is achieved through email validation.

Organizations can improve deliverability and safeguard their domain reputation by drastically lowering the risk of sending emails to invalid or incorrect addresses by verifying email addresses against the MX records. 

DNS configuration pages such as Bluehost can allow you to set up an MX record:

Understanding the nuances of role-based email addresses is crucial for effective email verification. Explore our guide on role-based email addresses for insights into handling these types of addresses in your email campaigns.

Advanced MX Record Strategies

Advanced MX record strategies involve sophisticated configurations that enhance email deliverability, security, and resilience against outages and spam. A notable tactic is "nolisting," a technique where the domain's primary MX record is intentionally set to a non-existent or unresponsive server, with secondary (lower priority) records pointing to the actual mail servers. 

This approach can mitigate spam by anti-spam filters and exploiting the behavior of many spammers who only attempt delivery to the highest priority MX record, thereby reducing unwanted email traffic without impacting legitimate email delivery.

Backup MX records serve as an essential safeguard for email systems, providing a failover solution in the event of a primary email server outage. These records ensure that incoming mail is redirected to a secondary server if the primary is unreachable, thus maintaining email continuity. 


From setup to troubleshooting, navigating MX Records can be challenging, particularly when trying to ensure optimal email deliverability and security. Although this information gives a good starting point, specialized knowledge is frequently needed due to the subtleties of email systems and DNS configurations.

Speak with an expert if this is your first time setting up MX Records, you're having problems with deliverability, or you want to improve your email infrastructure. They can help you resolve any problems that may come up, saving you time and guaranteeing the smooth operation of your email correspondence.

Professional assistance and verification services such as Mailchimp, are valuable resources that can help safeguard your email deliverability and enhance the security of your email communications. Don't hesitate to seek out their expertise to bolster your email infrastructure and support your communication needs.

Discover the top tools for enhancing your email services with our guide on the best email APIs.


How Do I Set Up MX Records?

You must gain access to your domain's DNS MX record settings, which are normally located in the control panel of your web hosting company or domain registrar, in order to set up MX Records. Once there, find the DNS record management section. To add an MX record, click on the "Create New Record" option, select MX as the type, and input the required information, including the mail server address and priority. After making your edits, save them and give the new configurations some time to spread throughout the internet.

How Can I Check My MX Records?

Online resources such as MXToolbox and Google Admin Toolbox allow you to verify your MX Records. These tools will show you your current MX Records, including the mail server addresses and their priorities, if you just enter your domain name server.

How Do MX Records Affect Email Deliverability?

Because they route incoming emails to the appropriate server, MX Records are essential for email deliverability. Emails are delivered to your mail server without any problems if your MX Records are set up correctly. 

Can Changing MX Records Impact Email Services?

It is true that altering MX Records may have an effect on your email services, particularly if the updated settings are off or the mail server address is spelled incorrectly. Email delivery may be disrupted or misdirected as a result of any modifications made to MX Records.

Are MX Records Related to Email Security?

MX Records themselves do not directly secure email communications, but they are part of a broader email infrastructure that includes security protocols.

Brian Wu
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